Ive Been On The Pill For Close To A Year

Ive been on the pill for close to a year now. Ive always had irregular periods (every three months for years before starting on the pill due to sports says my doctor) But is it possible to still have irregular periods even almost a year in? My first real one was back in august and I havent had one since. Maybe a little spotting here and there but nothing more. And I took a pregnancy test came back negative. Either the pill doesnt regurlar my periods? or I still have irregular periods?